1.1. Field of the Invention
Present invention relates generally to the detection of cervical cancer. More particularly, the present invention relates to an apparatus and method for the visual examination of cervical epithelium by means of a colposcopy assembly capable of producing a digital image of the cervix which is essentially free of reflective glare that otherwise masks or veils cancerous and pre-cancerous tissue.
1.2. Problems in the Art
1.2.1 General Setting of the Invention
Over the last fifty years, Papanicolaou Smear ("Pap Smear") has become the cornerstone of efforts to reduce cervical cancer mortality. Pap Smear is effective because it identifies the latest stages of cervical cancer. Current estimates are that 60-70 million Pap Smears are done in the U.S. each year. Pap Smear has, thus, become a norm in the detection of cervical cancer. In spite of its broad acceptance in the medical community, studies indicate that Pap Smear screenings will fail to detect from 50%-80% of low grade cancerous lesions, and even 15%-30% of high grade cancerous lesions.
1.2.2 Conventional Methods and Systems
When conducting Pap Smear screenings, the gynecologist collects exfoliated cells from the surface of the cervix and places them on slides that are sent to cytologists for further examination. Cytologists then review the cells placed on the slides and look for abnormal cells. If abnormal cells are found, the Pap Smear is considered to be positive. If no abnormal cells are found, the Pap Smear is considered to be negative. It is also possible that Pap Smear slides cannot be properly evaluated by the cytologist because of technical problems associated with the Pap Smear collection process such inadequate cell count, improper slide fixation, etc.
In the early stages of cervical disease, abnormal cell exfoliation is slow and most abnormal cells are located below the surface or are trapped by a keratin barrier covering the cervical surface. In these circumstances, the Pap Smear screening process is a relatively insensitive indicator of cervical health due to inaccessibility of abnormal cells that are otherwise indicators of cancerous or pre-cancerous tissue. HPV virus is the most common cause of keratin barriers to exfoliation. Further, it is commonly known that a significant portion of the U.S. population harbors the HPV virus which therefore, complicates the challenge of cervical cancer detection when using the Pap Smear as the principal screening procedure.
Because of a variety of problems associated with Pap Smear screening, it is well known that the Pap Smear procedure has both a high false negative, and a high false positive rate. Nevertheless, in spite of its cancer detection shortcomings, Pap Smear screening has become generally recognized as a practical and economical procedure for the early detection of cervical cancer. While the Pap Smear process is designed for initial screening, colposcopy, and related procedures, are generally used to confirm Pap Smear abnormalities and to grade cancerous and potential cancerous lesions.
Since its introduction in 1925, colposcopy has acquired wide recognition as a follow-up clinical procedure for patients identified by Pap Smear screening as having possible cervical abnormalities. It is generally recognized that colposcopy is highly effective in evaluating patients with abnormal Pap Smears and has therefore become the standard of medical care in the Western world for this circumstance. It is estimated that approximately 4 million colposcopy examinations are currently performed in the U.S. each year. Its routine use, however, is time consuming and costly. Further, proper colposcopy examinations are limited by the expertise of the examiner.
The recent emergence of computer-aided colposcopy creates a potential for the enhancement of colposcopic assessments. Computer-aided colposcopy provides for expanded utility in digital colposcopic photography and videography, and in the management of information generated by the colposcopic examination, including computer-aided processing and enhancement of colposcopic-generated images. Computer-aided colposcopy also sets up a platform that will facilitate the emergence and development of "telemedicine" by permitting the communication of diagnostic digital image information across tele-communication networks.
1.2.3 Shortcomings--Needs
Colposcopy, however, is faced with its own set of challenges. It is a subjective assessment and the quality depends greatly on the expertise of the practitioner. It is time consuming with significant legal risks associated with false negative evaluations, and is therefore expensive. Computer-aided colposcopy, while capable of generating, storing and manipulating image data for the production of high-quality images, is suffering certain technical difficulties. One of the greatest difficulties encountered is glare resulting from the reflection of colposcopic illumination from wet cervical tissue and its associated derogatory effect on visualized and captured image quality. Technical difficulties resulting from reflective glare have been reported in the literature as responsible for significant percentages of computer-aided colposcopic captured images rendered unreadable. In situations where traditional film photography-aided colposcopy have been evaluated, it has been similarly reported in the literature that a significant portion of photographic images are rendered unusable because of glare artifacts produced as a result of the reflections from the illumination used in the photographic image creation process.
Another difficulty is the formation of shadows from unevenly disbursed lighting used to illuminate the vaginal cavity for examination. Shadows either veil or distort the appearance of the area under examination.
Another difficulty with traditional photography-aided colposcopy is the long delay from the time a photograph is taken until it is developed so that photographic image may be seen. This delay is overcome with Polaroid film photography, but at the cost of an inability to produce high quality copies from the original. With such a delay, the patient may not be conveniently available to take another photograph in the event that the previous one was defective.
A two-fold need, therefore, exists in the area of cervical cancer screening and detection. A simple, low-cost colposcopic technique is needed for use in conjunction with the Pap Smear procedure that would improve the overall statistical accuracy of the screening effort. In addition, traditional colposcopy should be made easier to perform by reducing the subjectivity of the examination and should further be capable of producing archivable images that are devoid of technical flaws and inadequacies.
1.3. Objects, Features and Advantages of the Invention
In accordance with the present invention, a method and apparatus are disclosed for the removal of reflective glare from digital colposcopic photography and videography. The present invention enables real-time imaging and archiving of images of the entire cervix for the purpose of detecting cancerous and pre-cancerous tissue.
Thus, an object of the present invention is to provide a computer-aided colposcopy device, a so-called "digital colposcope," having non-invasive, digital camera capability that provides for glare removal and general image enhancement, documentation, and an image archival means.
Another object of the invention is to provide a unique light source for illumination of the cervical tissue during digital image generation.
Another object of the invention is to provide a wireless computer interface capability between the digital colposcope and a computerized digital image archival system.
Another object of the invention is to provide such a digital colposcope with improved screening and diagnostic capability, and which is useful to grade lesion severity that may be otherwise obstructed by glare.
Another object of the invention is to employ digital photographic techniques with the computer processing and display technology in order to provide relatively instantaneous presentation of the digital photographic image on a color computer display. Such display and computer being an integral part of the digital colposcope. This rapid feedback of image quality would allow a doctor to re-take any digital photographic images that were deemed unsatisfactory.
Another object of the invention is to physically mount the computer display in on the colposcope in a fashion that would allow the patient to view the digital photographic colposcopic image so that the doctor might better educate the patient as to the medical conditions of the colposcopic view.